The invention relates to crankshaft dampers, and more particularly to crankshaft dampers having a dual ring configuration with a mechanically fixed flexible medial elastomeric member for absorbing torsional and bending vibrations.
Devices for damping crankshaft vibrations have been known in the art for many years. During operation, a crankshaft on an internal combustion engine rotates in response to the periodic pulses from the cylinders as each fires in turn. This produces vibrations in the crankshaft that are detrimental to the long term life of the engine, as well as connected components.
A particular class of dampers relies on concentric rings connected by a flexible elastomeric member. The inner ring secures the damper to the crankshaft. The outer ring contacts a belt for power transmission. The elastomeric member is contained between the rings, either by adhesives or by mechanical means. The torsional impulses from the crankshaft are diminished or absorbed by the flexible elastomeric member as the crankshaft rotates. The elastomeric generally occupies a constant cross-section annular space between the rings.
Representative of the art is U.S. Pat. No. 5,231,893 (1993) to Sisco et al. which discloses a crankshaft vibration damper having an elastomer member positioned between a hub and an outer inertia member. A radially. outward or inward curvature of the hub and inertia member is selected to reduce crankshaft bending vibration.
Also representative of the art is U.S. Pat. No. 5,453,056 (1995) to Ullrich et al. which discloses a pulley. and a torsional vibration damper connected to the pulley by an axial rim and an elastomeric member.
The prior art dampers rely primarily on adhesives that are not environmentally friendly to connect the rings to the elastomeric element. Failure of the adhesive or the surrounding elastomeric can cause catastrophic failure of the damper and damage to the engine.
What is needed is a dual ring damper that has a mechanical connection to retain the elastomeric between the rings. What is needed is a dual ring damper that has a mechanical connection comprising a complex, non-arcuate cooperating profile. What is needed is a dual ring damper using an EPDM elastomeric as the damping medium. What is needed is a dual ring damper with expanded tuning capabilities and range of frequencies due to the profile and volume of the elastomeric. The present invention meets these needs.
The primary aspect of the present invention is to a dual ring damper that has a mechanical connection to retain the elastomeric between the rings.
Another aspect of the invention is to provide a dual ring damper that has a mechanical connection comprising a complex, non-arcuate cooperating profile.
Another aspect is to provide a dual ring damper using an EPDM elastomeric as the damping medium.
Another aspect is to provide a dual ring damper with expanded tuning capabilities and range of frequencies due to the profile and volume of the elastomeric.
Other aspects of the invention will be pointed out or made apparent by the following description of the invention and the accompanying drawings.
The invention comprises a dual ring damper. The damper comprises an inner ring for connecting the damper to a crankshaft. It also comprises an outer inertial ring for contacting a belt or the like. A flexible elastomeric material is mechanically contained in an annular space between the inner ring and the outer ring. The inner surface of the outer ring and the outer surface of the inner ring each describe a complex, non-arcuate cooperating profile or cross-section that mechanically fixes the elastomeric between them. The elastomeric does not use chemical adhesives to bond with either the inner or the outer ring, instead relying on the mechanical containment between the rings. The elastomeric in the preferred embodiment comprises EPDM.